Flameless combustion heaters are well known. They typically work on the principle that an appropriate hydrocarbon-based fuel, when in contact with a suitable catalyst in the presence of air (or oxygen), will undergo combustion and release heat. This heat can then be distributed and used for a variety of purposes.
A variety of patents describe the incorporation of such a device on a garment such as a jacket or a belt for providing heat to the body. They typically describe means of pumping the fuel, preheating the fuel-air mixture (often by ignition), and controlling the feeding of the mixture to a catalytic area and distribution of heat resulting from the reaction. These systems tend to add a lot of complexity and cost to the products to which they are incorporated.
Furthermore, these patents describe heaters which are often based on alkane fuels, preferably propane or butane. These fuels are gases, and as such do not lend themselves to being carried easily in portable applications including garments. When using liquid alcohols as fuels, the fuel-air mixture is preheated and ignited before catalytic combustion occurs. Fuels in this category include methanol, naphtha, and ethanol. It is advantageous to react them in the gas phase with air in the presence of a catalyst. Since alcohols are liquids under operating conditions, one way to achieve this goal is shown in U.S. Pat. No. 6,062,210, which describes means of feeding methanol fuel through pores placed in a feeding tube in close proximity to the catalyst. However, this method is not selective, in that the pores will also allow the passage of other substances, which may happen to be present with the methanol fuel. This method can also allow the passage of liquid fuel to flood the catalyst.
These and other shortcomings are overcome in the invention described herein.